Binary package “lib64z1-dev” in ubuntu focal

compression library - 64 bit - DO NOT USE EXCEPT FOR PACKAGING

 zlib is a library implementing the deflate compression method found
 in gzip and PKZIP. This package includes the development support
 files for building 64 bit applications.
 .
 This package should ONLY be used for building packages, users who do
 not need to build packages should use multiarch to install the relevant
 runtime.